module test(
    
);
    reg  [15:0] IR_;
    reg  [4:0]IR = 5'b01101;
    //assign IR_[15:5] = {11{IR[4]}};
   // assign IR_[4:0] = IR[4:0];
    initial begin
        IR_[15:5] = {11{IR[4]}};//IR_[15:5] = '{default:IR[4]};
        IR_[4:0] = IR[4:0];
        $display("The IR_ is %b",IR_);
    end
endmodule